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Search Results: 1 - 10 of 186 matches for " morphometrics "
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Traditional and Modern Morphometrics: Review
G?khan OCAKO?LU,?lker ERCAN
Turkiye Klinikleri Journal of Biostatistics , 2013,
Abstract: Morphometrics, a branch of morphology, is the study of the size and shape components of biological forms and their variation in the population. In biological and medical sciences, there is a long history of attempts to quantitatively express the diversity of the size and shape of biological forms. On the basis of historical developments in morphometry, we address several questions related to the shape of organs or organisms that are considered in biological and medical studies. In the field of morphometrics, multivariate statistical analysis is used to rigorously address such questions. Historically, these methods have involved the analysis of collections of distances or angles, but recent theoretical, computational, and other advances have shifted the focus of morphometric procedures to the Cartesian coordinates of anatomical points. In recent years, in biology and medicine, the traditional morphometric studies that aim to analyze shape variation have been replaced by modern morphometric studies. In the biological and medical sciences, morphometric methods are frequently preferred for examining the morphologic structures of organs or organisms with regard to diseases or environmental factors. These methods are also preferred for evaluating and classifying the variation of organs or organisms with respect to growth or allometry time dependently. Geometric morphometric methods are more valid than traditional morphometric methods in protecting more morphological information and in permitting analysis of this information.
Crocidura populations (Mammalia, Soricidae) from the Sicilian-Maltese insular area
Maurizio Sarà,Roberto Vitturi
Hystrix : the Italian Journal of Mammalogy , 1996, DOI: 10.4404/hystrix-8.1-2-4101
Abstract: Recent studies have shown the presence of a new endemic species of Soricidae, Crocidura sicula, in the Mediterranean area. Its karyotype consists of 36 chromosomes (NF = 56, NFa = 52) as previously recorded in specimens from Sicily and Gozo (Malta). Karyological analysis carried out in the present study on specimens from Marettimo (Egadi) and Ustica and on two additional Sicilian localities proved the presence of the same C. sicula karyotype. The multivariate analysis of skull and mandible of these populations revealed a pattern of geographic variation which is mainly related to a size decrease (76% of the total variability accounted for) in shrews living in the small islands around Sicily. The body biometrics of these insular shrews follows this trend, with some exceptions such as in Ustica, where shrews are relatively bigger. The shrews from Ustica show also melanic fur, which is darker than the grey-witheish colour found in conspecific populations. Such a phenotype could be the result of adaptation to the volcanic environment on this island. This latter population is, of all the small islands, the most divergent and differentiated from the mother-island; if considering its skull morphometrics (i.e. the residual 24% of total variability) and its body biometrics.
Morfometría de las especies de Vieja (Cichlidae) en ríos de la cuenca del Usumacinta, Chiapas, México
Soria-Barreto, Miriam;Rodiles-Hernández, Rocío;González-Díaz, Alfonso A.;
Revista mexicana de biodiversidad , 2011,
Abstract: we evaluated and compared morphological characteristics among the 6 species of vieja fernández-yépez, 1969 from usumacinta river. we analyzed 20 adults by specie, obtaining 33 measurements, which were standardized and analyzed with a discriminant analysis. we also performed a comparison of body shape among species, using the geometric morphometric analysis from digitalized images. traditional and geometric morphometrics allowed distinguishing each taxa. we found 10 discriminants measures, related with the head region and length of fins, only mouth position was different among more taxa. in both analyses, similarity relationships showed 2 groups, being v. bifasciata (steindachner, 1864) and v. synspila (hubbs, 1935) the most similar species. thin plate spline showed greater variation in the cephalic region, specifically in eyes and mouth position. morphometrics differences can be used for taxonomic identification in future works. the variation found in cephalic and trophic morphology can be a mechanism that promotes coexistence of species and explain the diversity of the group in this region.
Morphometrical aspects of adults of Gratiana spadicea (Klug) Coleoptera, Chrysomelidae) from Southern Uruguay
Revista Brasileira de Biologia , 1999, DOI: 10.1590/S0034-71081999000300008
Abstract: morphometrical data of pronotum, elytra, and total length of adult males and females of a gratiana spadicea population from southern uruguay are given. descriptions and illustrations of aedeagus and spermatheca are provided for the first time. females were significatively larger than males in total length. the coefficient of variation of the aedeagus measures ranged from 3.7% to 7.7%, and those of the spermatheca from 4.1% to 11.2%. the best value for the coefficient of determination was obtained for the reciprocal regression (1/y = a + bx) of the total length of the aedeagus versus the length from the apex to the basal region of the median lobe.
Dados morfométricos de aves de sub-bosque da regi?o leste de Mato Grosso do Sul
Piratelli, Augusto Jo?o;Melo, Fernanda Pereira de;Caliri, Roslaine Faustino;
Revista Brasileira de Zoologia , 2001, DOI: 10.1590/S0101-81752001000200001
Abstract: data on body mass and measurements of external characteristics (length, width and height of bill; tarsus, tail, wing and total lengths) for live birds from eastern mato grosso do sul state, central brazil are reported. mean, standard deviation and minimum and maximum values are show for 95 species.
Morphometrical aspects of adults of Gratiana spadicea (Klug) Coleoptera, Chrysomelidae) from Southern Uruguay
Revista Brasileira de Biologia , 1999,
Abstract: Morphometrical data of pronotum, elytra, and total length of adult males and females of a Gratiana spadicea population from southern Uruguay are given. Descriptions and illustrations of aedeagus and spermatheca are provided for the first time. Females were significatively larger than males in total length. The coefficient of variation of the aedeagus measures ranged from 3.7% to 7.7%, and those of the spermatheca from 4.1% to 11.2%. The best value for the coefficient of determination was obtained for the reciprocal regression (1/Y = a + bX) of the total length of the aedeagus versus the length from the apex to the basal region of the median lobe.
Consequence of Spodoptera litura Fabricius (Lepidoptera: Noctuidae) Morphometrics Reared on Different Cotton Varieties
D.A. Tithi,M.R. Amin,S.M.A. Hossain,H.M.S. Azad
Our Nature , 2010, DOI: 10.3126/on.v8i1.4318
Abstract: Morphometric characteristics of cotton armyworm Spodoptera litura were studied on cotton varieties CB9, CB10 and SR05. The morphometric parameters of the insect showed that the cotton variety SR05 revealed significantly the highest diameter of egg mass (7.4±0.4 mm). The cotton varieties showed significant effect on the length of different larval instars but the breadth of 3 rd and 4 th instar were statistically different. The studied cotton varieties as food sources did not affect pupal length and also the length and breadth of adults, but pupal breadth showed significant variation. The highest breadth (6.5±0.6 mm) of pupa was found when the insects were reared on SR05 variety. DOI: 10.3126/on.v8i1.4318
A Quantitative Assessment of the Morphology of the Piriform Aperture as an Indicator of Race  [PDF]
Seth Gardner
Forensic Medicine and Anatomy Research (FMAR) , 2015, DOI: 10.4236/fmar.2015.31002
Abstract: Piriform apertures from skulls in the Bass Collection at the University of Tennessee were examined. The morphology of the perform aperture from digital images was captured using Adobe Measuring Tool 9.0 and data analyzed with SPSS 17.0. Twenty-four linear measurements from a central point of the aperture as well as the perimeter were evaluated to quantify a difference between Black and White populations. The statistical analyses employed Discriminate Functional Analysis followed by Stepwise analysis. Discriminate functions were generated to predict to which group a skull belonged. A discriminate function produced an accuracy of 77.4%. Step-wise discriminate function analysis, using only three variables, produced an accuracy of 79.0%.
Three-dimensional geometric morphometrics of the African genus Lophuromys (Rodenta Muridae)
Marco Corti,Cristiana Di Giuliomaria,Walter Verheyen
Hystrix : the Italian Journal of Mammalogy , 2000, DOI: 10.4404/hystrix-11.1-4142
Abstract: Three-dimensional geometric morphometrics was used to investigate patterns of growth and differences in size and shape of the skull of three species of the African rodent genus Lophuromys, representing the two subgenera Lophuromys s.s. (represented by a population of L. flavopunctatus from Rwanda and a population of L. sikapusi from Ivory Coast) and Kivumys (represented by a population of L. woosnami from Rwanda). Procrustes superimposition was used to study variation in 21 three-dimensional landmarks. Differences in shape were visualised by using current available graphical morphometric techniques. Significant differences in centroid size were found both between species, sexes, and age classes. The pattern of growth in size is parallel between species, suggesting that it has been maintained after cladogenesis. No significant sexual dimorphism in shape has been found. Moreover, growth significantly affects the shape of the skull of L. flavopunctatus, but not that of L. sikapusi and L. woosnami. The main distinction in shape reflects thc phylogenetic occurrence of the two subgenera, i.e. Kivumis and Lophuromys s.s. However, the knowledge on the biology of these species is inadequate to exclude that any other adaptive factor (e.g. diet, climate, etc.) may have contributed in causing shape differences.
Relative warp analysis to study morphological variations in the genital capsule of Trichogramma pretiosum Riley (Hymenoptera: Trichogrammatidae)
Neotropical Entomology , 2002, DOI: 10.1590/S1519-566X2002000200007
Abstract: the influence of the host on the morphology of the male genital capsule of trichogramma pretiosum riley was studied by geometric morphometric analysis. specimens of the parasitoid obtained from 10 different lepidoptera host species were used. initially, landmarks were defined and cartesian coordinates (x and y) for each landmark of the genital capsule of all specimens were obtained. the anatomic landmarks transformed to cartesian coordinates were then analyzed by generalized orthogonal least-square procedure. consensus configuration of the genital capsule for all specimens was obtained and partial and relative warps were determined. fifteen landmarks generated 24 relative warps for each specimen. the ordination of the relative warps (a = 0), using shape components, separated t. pretiosum into four different hosts groups: (1 - alabama argillacea (hueb.), helicoverpa zea (bod.) and diatraea saccharalis (fabr.); 2 - danaus plexippus erippus (cramer), hamadryas feronia (linn.) and spodoptera frugiperda (j.e. smith); 3 - anticarsia gemmatalis hueb., bonagota cranaodes meirick and diaphania sp. and 4 - anagasta kuehniella (zeller). the two first axes of the relative warps explained 83.0% of the total variation of the genital capsule shape of the specimens. the main difference was at the anterior region of the posterior extension of the dorsal lamina of the genital capsule. although results obtained were initial and exploratory they have demonstrated that subtle shape differences in the male genital capsule can be detected by geometric morphometric analysis.
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